Specimens retrieved at revision provide the opportunity to understand failure modes and mechanisms. Failed implants are sent to Hamburg from all over the globe, from all manufacturers, for analysis and documentation. In a recent retrieval series a unique methodology was developed to assess the wear of metal-metal bearings. Surface coordinates are measured using a coordinate measurement machine and wear area and volume are estimated by fitting of the original sphere to unworn regions. Linear wear of as little as 3µm can be measured. Wear magnitudes are related to patient records, X-Ray and histological analysis. For educational purposes, reports are delivered to each surgeon documenting their particular revision case.
Witt, F., Bishop, N., Morlock, M.M., A new method to evaluate plastic deformation or wear of retrieved implants, ESB 2012, Lissabon, 2012
Morlock, M.M., Bishop, N., Zustin, J., Hahn, M., Rüther, W., Amling, M., Modes of implant failure after hip resurfacing: morphological and wear 67 retrieval specimens, J.Bone Joint Surg.Am. 90 Suppl 3:89-95, 2008
Morlock, M.M., Bishop, N., Stahmer, F., Zustin, J., Sauter, G., Hahn, M., Krause, M., Rüther, W., Amling, M., RVersagensgründe von Oberflächenersatzimplantaten der Hüfte. Eine Analyse von 250 Revisionspräparaten, Orthopäde 37 (7):695-703, 2008
M. M. Morlock, N. Bishop, W. Rüther, G. Delling, and M. Hahn, Biomechanical, morphological, and histological analysis of early failures in hip resurfacing arthroplasty, Proc.Inst.Mech.Eng H. 220 (2):333-344, 2006